The present invention relates to a box for transporting goods, in particular to a foldable box and here to a pretensioning mechanism for an unlocking mechanism.
In the known technology, boxes for transporting goods are known, wherein such boxes are implemented foldably in order to define a small volume in a down-folded state so that a plurality of non-used empty boxes may be transported together on a pallet, wherein the number of the boxes transported together in the down-folded state is substantially higher than the possible number of boxes which may not be folded or boxes which are in an up-folded state. Such boxes are, for example, used for the transport of vegetables or fruit but also for the transport of other goods from a manufacturer to a buyer, wherein after their arrival at the buyer, the boxes are either used for the presentation of the goods in sales rooms or are emptied. As soon as the goods have been removed from the boxes, for example by selling the same, the boxes are used again.
During transport from the manufacturer to the buyer, the boxes are in the up-folded state and contain goods, for example fruit or vegetables, and when returning the same the boxes are down-folded in order to reduce the volume of same and thus, as mentioned above, be able to transport a large number of boxes at the same time.
FIG. 1 shows a schematic illustration of such a known box. The box includes a floor 10 and four side walls 12, 14, 16, 18. One pair of sidewalls is opposite to each other and as illustrated in FIG. 1 the box includes two short sidewalls 12 and 14 which are opposite to each other and two long sidewalls 16 and 18 which are opposite to each other. The dimensions of the short and long sidewalls are generally selected depending on the transport pallets, wherein several such boxes are arranged in one layer. In the European area for example three such boxes are arranged adjacent to each other with their long sides and on one of the short sides of the series of arranged boxes, two boxes are arranged in a transverse way whose short side surfaces are adjacent.
At least two opposing side walls include grip holes so that the box may be gripped and carried. In the example illustrated in FIG. 1, each of the side walls 12 to 18 includes a corresponding grip opening 20, 22, 24, 26. The side walls 12 to 18 are arranged foldably with respect to the floor 10, i.e., the side walls 12 to 18 may be folded onto the floor 10 so that the volume of the box is reduced to a minimum for their transport back. It may, for example, be provided to first fold the short side walls 12 and 14 onto the floor 10 and subsequently turn down the long side walls 16 and 18, wherein in such a case the joints for the short side walls are arranged lower than the joints for the long side walls so that e.g., the floor in the area of the long side walls 16 and 18 has a higher frame than in the area of the short side walls 12 and 14.
For bringing about the necessitated stability of the up-folded box the side walls 12 to 18 may be locked with respect to each other, wherein in the example illustrated in FIG. 1 a locking of the end surfaces 12 and 14 to the neighboring ends of the long sides 16 and 18 takes place. The short side walls 12 and 14 may comprise one or several protrusions which engage corresponding recesses in the side walls, wherein the side walls then comprise protrusions having corresponding recesses accordingly directing into the direction of the inner side of the box. In addition to these elements, a locking element is provided by means of which the side walls are locked with respect to each other in their up-folded position. In FIG. 1, corresponding locking elements are schematically designated by reference numerals 28, 30, 32 and 34 at the upper corners of the box. The locking elements 28 to 34 each include two elements, for example a fixed element provided on the protrusions of the long side walls 16 and 18, which may engage a further element provided at the short side walls 12 and 18. For locking and unlocking the corresponding element of the short side walls 12 and 14 is implemented movably, i.e., movable between a locked position in which the element engages the elements of the long side walls and an unlocked position in which no engagement of the elements takes place so that the short side walls may be folded into the direction of the interior of the box.
In order to enable a movement of the moving elements of the short sides 12 and 14, each of the short sides additionally includes an unlocking mechanism 36, wherein in FIG. 1 only the unlocking mechanism of the short side 12 is illustrated, the short side 14, however, comprises a corresponding mechanism. The unlocking mechanism 36 includes an unlocking bar 38 extending across the short side wall 12. The unlocking bar 38 includes two ends 40 and 42 at which the unlocking bar 38 is connected to the corresponding locking elements 28 and 30 of the short side 12. In the example illustrated in FIG. 1, the unlocking bar 38 extends from its first end arcuately downward in the direction of the floor 10 and then in parallel to the floor below the grip opening past the same in order to then again extend upwards in a curved manner towards the second end 42. The short side wall includes two guiding grooves 44 and 46 in which the unlocking bar 38 is guided by means of guide pins 48 and 50. In FIG. 1, the unlocking bar is illustrated in its rest position in which the unlocking bar cooperates with the locking element such that the same are in their locked position. In order to cause an unlocking of the locking elements 28 and 30, the unlocking bar is moved upwards, i.e., in a vertical direction upwards when seen from the floor, whereby the locking elements of the side wall connected to the ends 40 and 42 of the unlocking bar get out of engagement from the corresponding locking elements of the side walls 16 and 18 so that an unlocking was executed and turning down the side wall is enabled.
As a secure locking is desired in the up-folded state of the box, it is necessitated to only enable a movement of the locking bar 38 in the unlocked position when this is desired, in particular a movement into the unlocking position, for example due to a shock or impact or the like is to be prevented.
For this reason, the known box according to FIG. 1 includes the pretensioning elements 52 and 54 which extend between the unlocking bar 38 and an upper frame 56 of the side wall 12. The pretensioning elements 52 and 54 are integrally connected to the unlocking bar 38. Further, the upper ends of the pretensioning elements 52 and 54 are mounted to a bottom side of the upper frame. Between the mounting points, an inclined portion of the pretensioning elements 52 and 54 extends so that the opposing end points of the pretensioning elements are arranged spaced apart from each other in the transverse direction of the side wall, whereby the necessitated restoring force is provided with a movement of the unlocking bar 38 into its unlocking position into the direction of the rest position.
With a movement of the unlocking bar into the above mentioned unlocking position, the inclined portion between the end points of the pretensioning elements 52 and 54 is extremely stressed as the two are mounted on both sides so that it turned out with boxes implemented according to FIG. 1 that after a finite number of transport cycles which each include upfolding and downfolding the box a break of the inclined portion of the pretensioning element took place so that a secure locking of the box by holding the unlocking bar in its rest position is not guaranteed over time with such boxes.